1. Field of the Invention
This invention relates generally to a dual offset derrick, and more particularly, but not by way of limitation, to a derrick that is asymmetrical about its z axis in both x and y directions and a complementary drilling floor arrangement.
2. Description of the Related Art
Modern energy drilling operations include a wide variety of equipment and elements that operate together and sequentially. A drilling floor supports much of the equipment and elements utilized in a drilling operation. The arrangement of equipment and elements on the drilling floor greatly influences the efficiency of the drilling.
Oil and gas drilling derricks are often supported by a hull via a cantilever. Examples of cantilever configuration include offshore platforms and offshore vessels. In such derricks, the design of the derrick tower and the layout of the drilling floor are vitally important to the balance of forces and the resulting load on the cantilever and the hull. One type of cantilever drilling derrick is utilized in offshore drilling wherein the drilling derrick is supported on cantilever beams. See, for example, Branham et al., U.S. Pat. No. 3,477,235.
Welsh, U.S. Pat. No. 6,481,931, recognizes that modern drilling realities result in overload of the cantilever, and attempts to balance the loads in a way that reduces overload. Welsh, however, requires an undesirable arrangement of elements on the drilling floor.
Based on the foregoing, it is desirable to provide a drilling derrick that allows for a more practical and efficient arrangement of elements on the drilling floor.